#!/bin/sh

set -e

COMMAND="$1"
KVER="$2"

ESP_MOUNTPOINT=/boot/efi

EFI_DIR=$(efibootmgr -v 2>/dev/null | awk '
        /^BootCurrent:/ { current=$2; }
        /^Boot....\* .*xen\.efi/ { 
            if ("Boot" current "*" == $1) {
                sub(".*File\\(", "");
                sub("\\\\xen.efi\\).*", "");
                gsub("\\\\", "/");
                print;
            }
        }')

if [ -z "$EFI_DIR" ]; then
    EFI_DIR="$ESP_MOUNTPOINT/EFI/qubes"
else
    EFI_DIR="$ESP_MOUNTPOINT$EFI_DIR"
fi

if [ ! -d "$EFI_DIR" ]; then
    # non-EFI system
    exit 0;
fi

case "$COMMAND" in
    add)
        if ! fgrep -q "[${KVER}]" $EFI_DIR/xen.cfg; then
            # take the default section and use it as a template for the new entry
            awk -F = --assign "kver=${KVER}" '
              /^\[/ {
                  # section header - previous section (if any) ended

                  # if default section already processed, that is all
                  if (in_default) exit;
                  in_global=0; 
                  in_default=0; 
              } 
              /\[global\]/ { 
                  in_global=1; 
              }
              /^\[/ {
                  if ("[" default_name "]" == $0) {
                      in_default=1;
                      print "[" kver "]";
                      next;
                  }
              }
              /^default=/ {
                  if (in_global)
                      default_name=$2;
              }
              /^kernel=/ {
                  if (in_default) {
                      sub("=[^ ]*", "=vmlinuz-" kver);
                  }
              }
              /^ramdisk=/ {
                  if (in_default) {
                      sub("=[^ ]*", "=initramfs-" kver ".img");
                  }
              }
              {
                  if (in_default) {
                      print;
                  }
              }' $EFI_DIR/xen.cfg >> $EFI_DIR/xen.cfg
            
            # then change the default
            sed -e "s/default=.*/default=$KVER/" -i $EFI_DIR/xen.cfg
        fi

        cp "/boot/vmlinuz-$KVER" "$EFI_DIR/"
        if [ -e "/boot/initramfs-${KVER}.img" ]; then
            cp -f "/boot/initramfs-${KVER}.img" "$EFI_DIR/"
        else
            dracut -f "$EFI_DIR/initramfs-${KVER}.img" "$KVER"
        fi
        ;;
    remove)
        # don't care about changing default= line - yum should prevent removing
        # currently running kernel
        if [ -r $EFI_DIR/xen.cfg ]; then
            awk -F = --assign "kver=${KVER}" '
              /^\[/ {
                  # section header - previous section (if any) ended

                  in_current=0; 
              } 
              /^\[/ {
                  if ($0 == "[" kver "]")
                      in_current=1;
              }
              {
                  if (!in_current) {
                      print;
                  }
              }' $EFI_DIR/xen.cfg > $EFI_DIR/xen.cfg.new
            mv $EFI_DIR/xen.cfg.new $EFI_DIR/xen.cfg
        fi
        rm -f "$EFI_DIR/initramfs-${KVER}.img"
        rm -f "$EFI_DIR/vmlinuz-${KVER}"
        ;;
esac